BattleBots Post-Fight Report #3 : Shatter! vs Kingpin

Surprise! Discovery posted our fight vs Kingpin to their facebook page! You can watch it here, in its entirety, without even logging into facebook:

https://www.facebook.com/watch/?v=3014283215309147

Check it out, then hit the jump for the post-fight breakdown!

For this fight we finally got a chance to use a configuration other than our anti-vertical setup, this time it was our anti-horizontal setup!

​You may have noticed that we used our solid titanium hammer, "Titan". This hammer is 1.5" thick grade 5 titanium. It's actually a bit lighter than our AR500 hardened steel hammer, "Ol Rusty", but it's stronger due to being significantly thicker . Because of this we like to use it vs big horizontal spinners where it is likely to take a lot of big hits.

You'll also notice we're not running the "fangs" on the front wedge. Those would be immediately torn off vs a horizontal, and we don't need to be ground scraping against an opponent like Kingpin. So we swapped out the fangs and also added a thicker front wedge behind the ablative armor. You can see the difference below.

This configuration shows our anti-vertical setup, with front fangs, Ol' Rusty, and thinner front wedge.

This configuration shows our anti-horizontal setup, without front fangs, with Titan, and with thicker front wedge. Similar, but very different.

So, after all that preparation this ended up being a pretty quick fight. Kingpin didn't really move much at the start, and then it exploded. That said we had maybe the most explosive hammer hit of all time!

As for Kingpin's movement, we actually were working with Kingpin to get the drive going before we knew we'd be facing them. We didn't sabotage them, I swear! They actually use the same motors and controllers for drive as Shatter! so we gave them our controller settings (they actually have about 15 hp of peak drive power! it's crazy strong). It was driving well in the test box, but the issue from what I heard was that a (some?) set screw(s) came loose in the drive system. Say it with me:

"Set screws suck! "
-Carlo Bertocchini

The bar on Kingpin however worked great. It is about 80 lbs and I believe spins at the top end of the speed limit. It's powered by a gigantic brushed motor... it's basically Tombstone in a different shape. The shape may seem odd but has done decently as "V for victory" in smaller scale at robogames. You can check it out here. We were pretty scared of that bar coming into this fight because we knew it would pack a wallop.

Something to understand about this fight is that Battlebots is a TV show and as such we want to put on a good show. It's probable we could have won by just not doing much and letting Kingpin be counted out. But that's a bit boring, it wouldn't get on TV, and it wouldn't make us or Kingpin look good. So we pushed them around to see if maybe they'd start moving, and that didn't really work, so then we went for another hit.

Now here's the thing... its' really fun to hit a big spinner when it's up to speed. Like, REALLY fun. We did this once in KoB and it looked really cool. So we tried it again. BOOM!

​What happens when you jam a big spinner with a hammer? Well, it's a lot like jamming a bike wheel with a stick. Check out our KoB hit vs Crossfire and our BB hit vs Kingpin below. (thanks to reddit user u/Robotcombat144 for putting this montage together!)

The bar jams against the hammer and tears our hammer into the spinner's frame in both instances. In this way we can use the spinner's power against themselves. Hammers don't cause damage? I beg to differ! You can even see Kingpin's wheel go flying off in the first impact.

Also, check out that arm flex! We use a thin (well, it's 1/2" thick, but it's relatively thin) titanium arm. The purpose of using a thin arm is to do exactly what you see here. We have stiffness in the direction the hammer hits, but can flex and absorb a direct hit from a big spinner.

After the KoB hit, the arm looked a bit like a potato chip (this is not good). We hadn't put the lightening holes in the right spot, and it seemed a bit too thin. 

This is still better than breaking in half, as it's usable for the rest of the match, but it's not the best result. So in the new revision for Battlebots we changed up the hole pattern to strengthen the areas that bent before, and thickened up the entire arm by ~20%. After the Kingpin fight there was no bend in the arm at all! Success!

Also notable: the hammer head did not come off! It didn't come off at KoB and it didn't come off here. I know we got a lot of flack (rightfully so) after the hammer head came off vs Witch Doctor. That was user error... we put in the wrong bolts. When we use the correct bolts, it doesn't come off! Yay! The hammer head is actually structurally held in place with several titanium fingers, which are extensions of the arm itself. The bolts hold the hammer onto the end, but the titanium fingers take the force during an impact.

This is a closeup those fingers and unfortunately you can see a crack in one of the 4 fingers. It seems the stiffer hammer arm applied more force to the joint. ​It probably would have lasted through most normal matches, but we're not sure how many big spinner hits it could take like this. We ended up having the onsite Lincoln welders fix it for us (thanks!) but didn't want to use it as the primary arm after that. So we went to one of our backup arms.

We also scratched up our front ablative armor panel and hammer head a tad. No biggy.

​The damage to Kingpin on the other hand was quite severe.

This is a top down shot of the internals of Kingpin. Not good! ALL of the electronics in that main frame area were unsalvageable. You're talking spin motor, spin controller, drive controllers, receivers, batteries. Thousands up in smoke. Something they didn't show in the broadcast is the extent of the fire that happened as a result of those two hammer hits:

This was the biggest fire of the event up to this point and we felt really, really bad about this. As we said, we wanted to put on a good show. We didn't intend to completely destroy them. Unfortunately this is always a risk in the Battlebox.

What actually happened here is that the bar on Kingpin smashed our hammer into their frame and this drove nearly all of their spinner's energy directly into their frame. Most spinner hits are indirect, but by jamming it like we did it transferred a lot more of the KE into the hit than normal. This collapsed the frame in and caused a battery fire. You can see the point of impact here:

In addition to this we had multiple hammer hits to their lid, and if you watch closely you can see their lid deform a bit, but we didn't do a lot of damage up top. They had several cross-members in their frame and we kept hitting those, or right near the edge, so didn't dent in the top very much. The spinner-jam seems to be what caused the fire.

We also want to say that the Kingpin team is awesome, Kevin and Steve are nothing but polite even after we cost them thousands and thousands of dollars. We hope to see them back next year (without the pesky set screws) as they've got a lot of power in that blade and an unforgettably fun theme.

This win put us at 2-1, our first time at the competition with a winning record. We were extremely excited and couldn't wait for our next match-up. Who would they give us? We had so many possibilities in mind but we did not guess who they ended up picking...

Tune in this week, Friday at 8pm on Discovery, to see how this epic matchup plays out, and tell all your friends too!!

Thanks for reading, and thanks for being fans!

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Scarves are also finally for sale! Not many available, get them while you can!

Lastly we'd like to thank our sponsors, without whom this wouldn't be possible:

frog
Meer Precision
TMS Titanium
BaneBots
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Stolen Item

One final thing before we go, my personal favorite button press of all time, Mary with a tiny hammer: